my "8mm-08"

[nekshot]

Bad case of boredom and lack of funds from christmas had me in the shop looking for a project that would produce a shot of adrenalin and I spied this new 8mm barrel that I accidently shot some military primers in and produced some rust. I had cleaned it and lapped it and gave it the Sentry bore conditioner treatment and I got to thinking. The 30-06 has the 308 but the 8mm is all alone. Why not take a 308 cartridge and open it up to 8mm and see what happens. So to make the story short here it is beside the 8mm and take alook at the barrel, I almost ran out of material till the bolt headspaced with masking tape on the cartridge head. I have been shooting it today and it loves 150 hornady's but we are all about casting here. So this afternoon I shot 1 groub of the lee 185 with blc2 and i groub with 16 gr 2400. Very promising clusters with no crazy fliers. I am using 300 sav and 307 win loads info and compromising from there. I looked the other day on the internet and saw it has been done before and the fella's called it a 8-08 and I kinda liked that. All the other projects if have going need reamer rentals so this i was able to complete with out any output!

[nekshot]

126554 What a dork, I forgot to down load this on proper post!!!

[ballistim]

Nice project & good idea, love both the .308 & .358W, look forward to hearing how this works out for you.

[TCLouis]

I am missing something here.

8MM is 7.92X57

308 is 7.62X51

If I have this right the 308 should be coming up 6mm short.

[nekshot]

its a 308 case opened up to 8mm hence 8-08 or correctly 8mmx51, with this kinda carrying on we don't get too technical with certain details!

[skeet1]

TCLouis (http://castboolits.gunloads.com/member.php?171-TCLouis)
No you are not missing anything. If you look at the photo of the rifle it shows the collar on the barrel has just enough to bare against the action ring. This is because nekshot (http://castboolits.gunloads.com/member.php?6904-nekshot) had to cut so much of the chamber off the barrel that he almost didn't have enough collar left. Good job nekshot!

[tomme boy]

Still had the inner ring. A lot of mausers are that way anyway.

[FrankG]

Did you cut a 8mm die back for sizing ?

[nekshot]

Did you cut a 8mm die back for sizing ?

I will get a lee RGB set and cut those. So far I only used my rcbs to open the neck to 8mm and I have been using a lee 308 fact crimp to tighten the neck. When you mess around with this stuff you make do with what you got, a vise, a door jam any thing till you know what you actually need and of course you mention it to some and they see you as the stupidist hayseed to come drifting along. That is fine with me because my first goal is to be safe and after that get the dream idea to work!

[FrankG]

Been there done that . What ever it takes to get it loaded proper .

[TCLouis]

skeet1

You supplied the missing detail that made it work.

Funny how a little barrel setback makes all the difference.

7.92X51 should pretty decent performer and "Hey Why Not"?

[Yodogsandman]

What a great idea! Good job there nekshot! Keep us all informed on your tooling and load development. I might have a few 8mm barrels in the barn. Hope they're not too rusted.

[claude]

[smilie=p:[smilie=p:[smilie=p:Sorta like an 8mm short.:groner:

[izzyjoe]

Funny thing I was thinking the very same thing awhile back, cause I'm getting tired of forming brass from 30-06. I figured this would be less work, and I have more 308 brass anyways. Just about much did you cut off the shoulder? I also had the same theory about using a 7mm barrel that come off a Spanish mauser that I have from the last project.

[koehlerrk]

Just about much did you cut off the shoulder? I also had the same theory about using a 7mm barrel that come off a Spanish mauser that I have from the last project.

I'd guess he cut off about 6mm... maybe a hair more. Nice part about starting with a 7mm Mauser is that 7mm-08 is a very popular round, easy to get dies and brass.

[izzyjoe]

That's what I thinking, I'm not sure but it think the two 7mm's have different tappers to them, the whole ideal was to set the barrel back and no need for a reamer, just fire form brass and use low pressure loads.

[koehlerrk]

I'd recommend a reamer... see, while both the 7mm-08 and 7x57 have the same head diameter and neck diameter, what you'd be doing is cutting 6mm off the back end of the 7x57, effectively shortening the case, and you'd have one heckuva time shoving a round in since the base would want to stop about 6mm out...

Think of it this way, if you had a shot-out 7mm-08, rechambering to 7x57 would be a no-brainer because you're removing 6mm of material at the front of the cartridge. Setting it back 6mm, you're too far forward on the taper and you'll never get the bolt closed.

However, it would be child's play to take a reamer and gently make it fit the 7mm-08. Easy.